Processes for producing isothiazole derivatives

Abstract

A method for producing a 1,2-benzisothiazole characterized by treating a 2-(alkylthio)benzaldehyde oxime with a halogen compound; a method for producing a 3-halo-1,2-benzisothiazole characterized by treating a 1,2-benzisothiazole with a halogenating agent; and a method for producing a 1-(1,2-benzisothiazol-3-yl)piperazine characterized by reacting the obtained 3-halo-1,2-benzisothiazoles with a piperazine. By the method of the present invention, 1,2-benzisothiazoles and 3-halo-1,2-benzisothiazoles, which are useful as intermediates for pharmaceutical compositions such as psychotropic agents, and 1-(1,2-benzisothiazole-3-yl)piperazines synthesized therefrom can be obtained in a high yield without using expensive starting materials by shorter and simpler process than conventional methods.

We claim: 
     
       1. A method for producing a 1,2-benzisothiazole represented by the general formula (II), characterized by treating a 2-(alkylthio)benzaldehyde oxime represented by the general formula (I): ##STR5## wherein R 1  represents an alkyl group having 1 to 4 carbon atoms; and R 2  represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a nitro group, a carboxyl group or an ester thereof, or a halogen atom, with a halogen compound to give a 1,2-benzisothiazole represented by the general formula (II): ##STR6## wherein R 2  has the same definition as R 2  in the general formula (I).   
     
     
       2. The method according to claim 1, wherein the halogen compound is thionyl chloride. 
     
     
       3. The method according to claim 1, wherein the halogen compound is phosphorus oxychloride. 
     
     
       4. The method according to any one of claims 1 to 3, wherein the compound represented by the general formula (I) is 2-(methylthio)benzaldehyde oxime. 
     
     
       5. A method for producing a 3-halo-1,2-benzisothiazole represented by the general formula (III), characterized by reacting a 1,2-benzisothiazole represented by the general formula (II): ##STR7## wherein R 2  represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a nitro group, or a carboxyl group or an ester thereof, with a halogenating agent to give a 3-halo-1,2-benzisothiazole represented by the general formula (III): ##STR8## wherein X represents a chlorine atom or a bromine atom; and R 2  has the same definition as R 2  in the general formula (II).   
     
     
       6. The method according to claim 5, wherein the halogenating agent is chlorine or bromine. 
     
     
       7. The method according to claim 5, wherein the halogenating agent is sulfuryl chloride. 
     
     
       8. The method according to claim 5, 6, or 7, wherein the compound represented by the general formula (II) is 1,2-benzisothiazole. 
     
     
       9. A method for producing a 3-halo-1,2-benzisothiazole represented by the general formula (III), characterized by treating a 2-(alkylthio)benzaldehyde oxime represented by the general formula (I): ##STR9##  wherein R 1  represents an alkyl group having 1 to 4 carbon atoms; and R 2  represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a nitro group, a carboxyl group or an ester thereof, or a halogen atom,   with a halogen compound to give a 1,2-benzisothiazole represented by the general formula (II): ##STR10##  wherein R 2  has the same definition as R 2  in the general formula (I); and   reacting the obtained 1,2-benzisothiazoles with a halogenating agent to give a 3-halo-1,2-benzisothiazole represented by the general formula (III): ##STR11##  wherein X represents a chlorine atom or a bromine atom; and R 2  has the same definition as R 2  in the general formula (II).   
     
     
       10. The method according to claim 9, wherein the halogen compound is thionyl chloride. 
     
     
       11. The method according to claim 9, wherein the halogen compound is phosphorus oxychloride. 
     
     
       12. The method according to claim 9, wherein the halogenating agent is chlorine or bromine. 
     
     
       13. The method according to claim 9, wherein the halogenating agent is sulfuryl chloride. 
     
     
       14. The method according to claim 9, 10, 11, 12 or 13, wherein the compound represented by the general formula (I) is 2-(methylthio)benzaldehyde oxime. 
     
     
       15. A method for producing a 1-(1,2-benzisothiazol-3-yl)piperazine represented by the general formula (V), characterized by treating a 2-(alkylthio)benzaldehyde oxime represented by the general formula (I): ##STR12##  wherein R 1  represents an alkyl group having 1 to 4 carbon atoms; and R 2  represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a nitro group, a carboxyl group or an ester thereof, or a halogen atom,   with a halogen compound to give a 1,2-benzisothiazole represented by the general formula (II): ##STR13##  wherein R 2  has the same definition as R 2  in the general formula (I);   reacting the obtained 1,2-benzisothiazoles with a halogenating agent to give a 3-halo-1,2-benzisothiazole represented by the general formula (III): ##STR14##  wherein X represents a chlorine atom or a bromine atom; and R 2  has the same definition as R 2  in the general formula (I); and   reacting the 3-halo-1,2-benzisothiazoles with a piperazine represented by the general formula (IV): ##STR15##  wherein R 3  represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a substituted alkylene group having 1 to 6 carbon atoms, to give a 1-(1,2-benzisothiazol-3-yl)piperazine represented by the general formula (V): ##STR16##  wherein R 2  has the same definition as R 2  in the general formula (I); and R 3  has the same definition as R 3  in the general formula (IV).